ELM327 v1.4b

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Almost all of the automobiles produced today are required, by law, to provide an interface for the connection of diagnostic test equipment. The data transfer on these interfaces follow several standards, but none of them are directly usable by PCs or smart devices. The ELM327 is designed to act as a bridge between these On-Board Diagnostics (OBD) ports and a standard serial interface.

In addition to being able to automatically detect and interpret nine OBD protocols, the ELM327 also provides support for high speed communications, a low power sleep mode, and the J1939 truck and bus standard. It is also completely customizable, should you wish to alter it to more closely suit your needs.

The data sheet discusses all of the ELM327’s features in detail, how to use it and configure it, as well as providing some background information on the protocols that are supported. There are also schematic diagrams and tips to help you to interface to microprocessors, construct a basic scan tool, and to reduce power consumption.

If you are wondering what the differences are between the many ELM327 versions, you may find the Version History section in Help / OBD / Tips to be helpful.


  • Diagnostic trouble code readers
  • Automotive scan tools
  • Teaching aids


  • Power Control with standby mode
  • RS232 baud rates to 500 kbps
  • Automatically searches for protocols
  • Fully configurable with AT commands
  • Low power CMOS design

Connection Diagram

( PDIP or SOIC, top view )
ELM327 v1.4b connection diagram

Block Diagram

ELM327 v1.4b block diagram


The ELM327 v1.4b data sheet (373K):

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The ELM327 v1.4b data sheet iBook (11MB):


Quantity Pricing

The following are the unit prices, as you vary the quantity purchased:






All prices are in Canadian dollars. We use the total number of ELM327 v1.4b ICs purchased (327P_V14 + 327SM_V14) for the calculation.


Select the desired integrated circuit package type, then the quantity desired, before adding it to your shopping cart. Quantity discounts will be applied as appropriate.

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Once our stock is gone, this IC will no longer be available. Do not use for new designs – consider the ELM327 v2.2.

Alternative Labelling

To help us meet demand, Microchip Technology has been programming and labelling some of the ELM327SM chips for us. These ICs may look different, but are functionally identical. You may receive ICs that look like those shown above, or as shown below. The differences are only in appearance:

sku: 327SM_V14

Related Products

The following offer more advanced versions of the ELM327 firmware:

And you may find it convenient to order CAN transceivers from us: